A Program from Tron.  Perhaps calc.exe or something of that nature.

It’s Clu, the hacker program from Tron!  Actually, it is, but now he’s been undeleted and recoded to be a dick.  Once used to infiltrate Cyberdine, er.. Encom, Clu later became the task manager for the computer world infrastructure.  Driven mad by his impossible goal for perfection, Clu turned from creation to destruction, even going as far as to attempt to correct the existence of his own creator.

This is a generic “User” in the style of the modern Tron film.

“That’s Tron.  He fights for the users.”